The Patient-Specific Functional Scale: validity in workers' compensation claimants.

Abstract

To examine the construct and predictive validity of the Patient-Specific Functional Scale (PSFS) in workers' compensation claimants. Prospective cohort study with 1-year follow-up. A workers' compensation rehabilitation facility. Subjects included 294 claimants with a variety of musculoskeletal disorders. The sample was predominantly male (70%), with a mean age of 44 years. Subjects completed a battery of measures at baseline including the PSFS, the Pain Disability Index (PDI), and the Medical Outcomes Study 36-Item Short-Form Health Survey (SF-36). Not applicable. Outcomes for determining predictive validity included administrative indicators of timely return to work and recovery during the 1-year follow-up. Analysis included Pearson correlation and multivariable Cox and logistic regression. At baseline, the PSFS correlated moderately (r range, 0.3-0.5) with other indicators of functional limitation (PDI, SF-36 role-physical subscale) but negligibly with the SF-36 mental health and role-emotional subscales. The PSFS was associated with timely recovery (adjusted hazard ratio, 1.16; 95% confidence interval, 1.07-1.27) with increasing functional limitation related to delayed recovery. Results provide construct and predictive validity evidence for the PSFS as an indicator of functional limitation in workers' compensation claimants.